/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.confignode.procedure.impl.schema;

import org.apache.iotdb.common.rpc.thrift.TConsensusGroupId;
import org.apache.iotdb.common.rpc.thrift.TDataNodeLocation;
import org.apache.iotdb.common.rpc.thrift.TRegionReplicaSet;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

class DataNodeRegionGroupUtil {

    private DataNodeRegionGroupUtil() {
    }

    /**
     * Try to get and execute request on consensus group leader as possible. If fail to get leader,
     * select some other replica for execution.
     */
    static Map<TDataNodeLocation, List<TConsensusGroupId>> getLeaderDataNodeRegionGroupMap(
            Map<TConsensusGroupId, Integer> leaderMap,
            Map<TConsensusGroupId, TRegionReplicaSet> regionReplicaSetMap) {
        Map<TDataNodeLocation, List<TConsensusGroupId>> dataNodeConsensusGroupIdMap = new HashMap<>();
        regionReplicaSetMap.forEach(
                (consensusGroupId, regionReplicaSet) -> {
                    Integer leaderId = leaderMap.get(consensusGroupId);
                    TDataNodeLocation leaderDataNodeLocation = null;
                    if (leaderId == null || leaderId == -1) {
                        leaderDataNodeLocation = regionReplicaSet.getDataNodeLocations().get(0);
                    } else {
                        for (TDataNodeLocation dataNodeLocation : regionReplicaSet.getDataNodeLocations()) {
                            if (dataNodeLocation.getDataNodeId() == leaderId) {
                                leaderDataNodeLocation = dataNodeLocation;
                                break;
                            }
                        }
                    }
                    dataNodeConsensusGroupIdMap
                            .computeIfAbsent(leaderDataNodeLocation, k -> new ArrayList<>())
                            .add(regionReplicaSet.getRegionId());
                });
        return dataNodeConsensusGroupIdMap;
    }

    /**
     * Try to execute request on all replica of one consensus group. If some replica failed, execute
     * according request on some other replica and let consensus layer to sync it.
     */
    static Map<TDataNodeLocation, List<TConsensusGroupId>> getAllReplicaDataNodeRegionGroupMap(
            Map<TConsensusGroupId, TRegionReplicaSet> regionReplicaSetMap) {
        Map<TDataNodeLocation, List<TConsensusGroupId>> dataNodeConsensusGroupIdMap = new HashMap<>();
        regionReplicaSetMap.forEach(
                (consensusGroupId, regionReplicaSet) -> {
                    for (TDataNodeLocation dataNodeLocation : regionReplicaSet.getDataNodeLocations()) {
                        dataNodeConsensusGroupIdMap
                                .computeIfAbsent(dataNodeLocation, k -> new ArrayList<>())
                                .add(regionReplicaSet.getRegionId());
                    }
                });
        return dataNodeConsensusGroupIdMap;
    }
}
